Royal Enfield and the Secret of Magura

Magura twist grip and its "perch" have a secret.

 The members of The Unofficial Royal Enfield Community Forum diagnosed my problem almost instantly. They were so on the mark that they even caught me in a small lie. 

I asked what could have made the motor of my 1999 Royal Enfield Bullet run away, its rpm surging as I sat innocently at a stop light. 

"Are you absolutely sure you didn't touch anything? You didn't blip the throttle? Your hands were definitely off the bike? If so, then suddenly deciding to rev its nuts off entirely of its own volition is beyond weird," wrote forum member Steve Thackery. 

"If you did touch something, that would be very useful information for the diagnosis." 

Right on the money. I wasn't innocent. Sitting at the light I had felt the Bullet was idling a bit fast. I experimentally gave a tug on the throttle cable on its run from the twist grip to the nacelle. The Bullet immediately begun roaring.

I hadn't wanted to admit this clumsy move.

Forum members correctly suggested I check the twist grip. I did and, to my horror, found the throttle outer cable out of its socket on the outside of the twist grip assembly and the inner cable unwound and curled outside its housing.

I posted a photo of this on the forum. Members suggested buying a new cable and new controls.

This could be a problem for my Bullet, built in early 1999.

The handlebar controls on Royal Enfield Bullets manufactured 1988 to mid-1999 were made by Magura, a German company; Royal Enfield switched to made-in-India Minda controls for the Bullet in June, 1999. The old Magura gear has now been unavailable for many years.

Luckily, Hitchcocks Motorcycles sells a kit to replace the Magura controls with Minda versions, which are old themselves but still available.

"Swapping over to the 'newer' Minda hardware lets you keep ready access to current control cables, better levers and better electrics. Well worth the time and trouble," forum member AzCal Retred advised, helpfully. That is the kind of information that is really useful.

But wait: what if I could just fix my Magura twist grip? I decided to try. I already had an unused spare Magura style throttle cable.

Well, first, there didn't appear to be any way to connect my new throttle cable without removing the twist grip from the bike. (There is, but I would discover it only later. It's THE MAGURA SECRET.)

Twisting, tugging, sweating, and swearing finally got the twist grip to come off, in my hands. It was obvious now how to attach my new cable. The barrel shaped end tucks into a tight nook in the rubber grip and is held there.

But no amount of violence or dirty words would convince the twist grip to reconnect to its "perch." The perch is the plastic module that holds the twist grip, the throttle cable, kill switch, rear brake light switch, front brake cable and lever, and rearview mirror.

My hoped for repair seemed doomed.

I finally found the answer, on the Myrons Mopeds website. (Apparently Magura throttles, of related but not identical design, were used on a variety of mopeds.)

THE SECRET: The twist grip will neatly snap onto the perch ONLY if both are OFF the handlebar! It is the handlebar itself that holds the assembly together.

If you are still with me here, you realize that I had only pulled the twist grip off; to get the perch off I would now have to disconnect the kill switch, throttle cable, front brake cable, and rear brake light switch. I could do all that, in time, in my garage.

Imagine having to do all that, and then reconnecting it all on the side of the road, just to swap in a new throttle cable. Impossible! What was Magura thinking?

Well they were thinking. And there is a way. I wouldn't even have had to remove the twist grip.

Silver throttle cable barrel is just visible if you peel back the rubber flange of the Magura twist grip.

Here is the incredible REST OF THE SECRET, again from Myrons Mopeds:

"Peel the flange of the grip there back with your thumb, and hold it there. With the other hand, place the sideways barrel end of the throttle cable into the cavity. Lay the wire over the ridge, and wrap it around the curved guide. When pulled taut it should fall into it’s groove. The throttle should pull the wire and move free."

Would you have thought of it? Just peel back the rubber grip and pull the old cable barrel out, all with the grip still in place. Then pop in the barrel of the new cable and let the carburetor spring pull the cable taught.

It works! But you had better have a needle-nose pliers in your toolkit if you ever need to do this by the side of the road.